Here we put Ado::Command::* specific configuratuon files.
The files must be named after the commands for which they contain configuration.
A command Ado::Command::hello will search its configuration
first in the common etc/ado.conf at $app->config('commands')->{hello};
then in
$app->home->rel_dir('/etc/commands/hello.conf').
The file must return a HASHREF:
(the app keyword containing the current application instance 
  is available for use)
#hello.conf
{
  somekey =>'somevalue'
  #...
};